For a long time, beeswax has been in common usage as a natural wax for candles. Over one hundred years ago, paraffin came into existence, in parallel with the development of the petroleum refining industry. Paraffin is produced from the residue leftover from refining gasoline and motor oils. Paraffin was introduced as a bountiful and low cost alternative to beeswax, which had become more and more costly and in more and more scarce supply.
Today, paraffin is the primary industrial wax used to produce candles and other wax-based products. Conventional candles produced from a paraffin wax material typically emit a smoke and can produce a bad smell when burning. In addition, a small amount of particles (“particulates”) can be produced when the candle burns. These particles may affect the health of a human when breathed in. A candle that has a reduced amount of paraffin would be preferable.
Accordingly, it would be advantageous to have other materials that can be used to form clean burning base wax for forming candles. If possible, such materials would preferably be biodegradable and be derived from renewable raw materials, such as natural oil based materials. The candle base waxes should preferably have physical characteristics, e.g., in terms of melting point, hardness and/or malleability, that permit the material to be readily formed into candles having a pleasing appearance and/or feel to the touch, as well as having desirable olfactory properties.
Additionally, there are several types of candles, including taper, votive, pillar, container candles and the like, each of which places its own unique requirements on the wax used in the candle. For example, container candles, where the wax and wick are held in a container, typically glass, metal or the like, require lower melting points, specific burning characteristics such as wider melt pools, and should desirably adhere to the container walls. The melted wax should preferably retain a consistent appearance upon resolidification.
In the past, attempts to formulate candle waxes from natural oil-based materials have often suffered from a variety of problems. For example, relative to paraffin-based candles, natural oil-based candles have been reported to exhibit one or more disadvantages such as cracking, air pocket formation, and a natural product odor associated with vegetable oil materials such as soybean oil. Various soybean-based waxes have also been reported to suffer performance problems relating to optimum flame size, effective wax and wick performance matching for an even burn, maximum burning time, product color integration, and/or product shelf life. In order to achieve the aesthetic and functional product surface and quality sought by consumers of candles, it would be advantageous to develop new natural oil-based waxes that overcome as many of these deficiencies as possible.
There are fundamental differences in the inherent properties of the renewable, natural oil based saturated triglycerides when they are compared to the petroleum based straight chain aliphatic hydrocarbons that make up paraffin wax. Triglycerides exhibit well-documented polymorphic behavior whereas the aliphatic hydrocarbons of paraffin do not. “Polymorphism” means there are multiple crystal forms of the material that can (co)exist. In general, under rapid cooling, less stable lower melting and less molecularly dense crystals form initially, but given time and freeze-thaw cycles, the mobility of the molecules allow their rearrangement to higher melting, more stable and more molecularly dense crystal forms. This rearrangement can lead to the problems of cracking and blooming (i.e., “fat blooming”) in a candle produced from natural oil based wax.
Fat blooming of a candle wax composition, as a consequence, results in a loss of sales and increased handling and production costs to the manufacturer. As a result, there is continuing interest in developing candle waxes substantially free of fat bloom from natural oils and natural oil derivatives.